For example, in a photolithography process of a semiconductor device manufacturing process, for example, a resist coating processing of applying a resist liquid to a processing target film on a surface of a semiconductor wafer (hereinafter, referred to as a “wafer”) to form a resist film, an exposure processing of irradiating a predetermined pattern of light is irradiated on the resist film on the wafer to expose the resist film, and a development process of developing the exposed resist film are sequentially performed such that a predetermined resist pattern is formed on the wafer. After the resist pattern is formed, the processing target film is etched by using the resist pattern as a mask such that the predetermined pattern is formed on the processing target film.
Due to the exposure processing, fine unevenness called line edge roughness (LER) appears on a side surface of the resist pattern formed by the photolithography processing. The unevenness of the side surface of the resist pattern is transferred onto the processing target film during the etching and the unevenness becomes impossible to ignore as high speed operation and miniaturization of a semiconductor device has progressed in recent years.
Regarding the LER, a technique is known in which, for example, the resist pattern is heated so as to improve the LER. For example, Japanese National Phase Publication No. 2001-332484 discloses a method of improving line edge roughness by irradiating ultraviolet ray on a wafer to heat a resist pattern.